X-Git-Url: http://git.giacomolli.uk/onechat/blobdiff_plain/6b21fcf78372995c6d8130c63f2f8aa2609bf7fe..5bb22ac2fc501bad7327c119f1d3ac514e3d5398:/telegram.go?ds=sidebyside

diff --git a/telegram.go b/telegram.go
index 13c200c..6d5332d 100644
--- a/telegram.go
+++ b/telegram.go
@@ -311,9 +311,9 @@ func (b *TelegramBot) typing(ctx context.Context) {
 }
 
 // post sends event to the chat. A reply goes as rich messages of its Markdown,
-// with each < outside code escaped by telegramEscapeTags and then split with
-// telegramSplitRich, so that the length limit counts the escaped text. Every
-// other event goes as plain text, split with telegramSplitMessage.
+// with each < and & outside code escaped by telegramEscapeTags and then split
+// with telegramSplitRich, so that the length limit counts the escaped text.
+// Every other event goes as plain text, split with telegramSplitMessage.
 func (b *TelegramBot) post(ctx context.Context, event Event) {
 	if event.Kind != "reply" {
 		for _, text := range telegramSplitMessage(telegramText(event), telegramMessageUnits) {
@@ -411,11 +411,13 @@ func (b *TelegramBot) deliver(ctx context.Context, part TelegramPart) {
 	}
 }
 
-// deliverRich sends markdown to the chat as a rich message. When the Bot API
-// refuses it with HTTP 400 or 404, the message was not sent, so deliverRich
-// sends the same Markdown once with message entities, and the reply is not
-// lost and does not repeat. It tries again after each failure that a later try
-// can fix, until ctx ends. It drops the message after any other failure.
+// deliverRich sends markdown, escaped with telegramEscapeTags, to the chat as a
+// rich message. When the Bot API refuses it with HTTP 400 or 404, the message
+// was not sent, so deliverRich sends the text of the part once with message
+// entities, and the reply is not lost and does not repeat. Message entities
+// read no HTML, so the fallback gets the Markdown of telegramUnescapeTags, as
+// the model wrote it. It tries again after each failure that a later try can
+// fix, until ctx ends. It drops the message after any other failure.
 func (b *TelegramBot) deliverRich(ctx context.Context, markdown string) {
 	wait := b.minWait
 	for {
@@ -426,7 +428,7 @@ func (b *TelegramBot) deliverRich(ctx context.Context, markdown string) {
 
 		if telegramRejected(err) {
 			b.logger.Printf("rich message refused, the reply goes with entities: %v", err)
-			for _, part := range telegramReplyParts(markdown) {
+			for _, part := range telegramReplyParts(telegramUnescapeTags(markdown)) {
 				b.deliver(ctx, part)
 			}
 
@@ -546,7 +548,8 @@ func telegramText(event Event) string {
 // after the last line break outside a code block, then after the last line
 // break in a code block, which it closes at the end of the part and opens again
 // in the next part with the same fence line. A line longer than limit is cut at
-// the limit. It never cuts a character.
+// the limit, or before an & in the four bytes before the limit, so that it does
+// not cut an entity of telegramEscapeTags. It never cuts a character.
 func telegramSplitRich(markdown string, limit int) []string {
 	var parts []string
 	for len(markdown) > limit {
@@ -649,6 +652,12 @@ func telegramRichCut(markdown string, limit int) (int, string, string) {
 		cut--
 	}
 
+	start := max(cut-len("&amp;")+1, 0)
+	entity := strings.LastIndexByte(markdown[start:cut], '&')
+	if entity >= 0 && start+entity > 0 {
+		cut = start + entity
+	}
+
 	return cut, "", ""
 }